Gee, it is so nice to hear from you that sandbox is an invented term and that is a myth according to Google. To be honest I am annoyed by the new terms that I encounter like sandbox and that black hat and others because it is obvious that those terms were just coined by a creative user. Instead of helping people learn SEO methods those terms add to the confusion and I’d say that I get a headache with those terms.

Some people say its a myth, but what it actually is a mixture of different algorithms. Nobody has ever got any message in their Webmaster Tools error console that said your site was moved into a sandbox as on the Internet and in any Google datacenters around the world, there is no such place exists that could even remotely be considered or seen as a sandbox. A sandbox after all, is a safe place, it's where you put your kids to play in. But nowhere exists like this on the Internet. Not even a virtual one created by Google. So what's really going on when your site has been deindexed and delisted from the SERPS is that it's been flagged by several different algorithms at once and is suffering because of it. That is probably a much more likely scenario. But if it has been deindexed and delisted then it was definitely done so for a reason. The first thing to do in that situation would be to find out what that reason is and do something about it. That's why Google provide Webmaster Tools Console you can add your site to so it will be able to tell you what the penalty is for in broad terms for you to do something about that you can then go on to fix and clean up and then submit a manual reconsideration request, cross your fingers and pray for good news.

To be honest, this is just the second time that I have encountered this term Sandbox in Google. I ignored the first time but now I guess I have to understand this. And I’m glad that it may just be a myth that you get to be sandboxed when your site is over optimized. Maybe that over optimized may mean too much use of keywords which they call keyword stuffing. I am sometimes confused whenever I would come across new terms that are invented for SEO work.